I could not find the old thread, so I'm staring a new one. Post any free game links you find here.
SOMA for PC is free until Jan 3 from GOG.com: https://www.gog.com/game/soma
The game gets very good reviews and looks very fun.
More free games at Epic's holiday sale. Keep checking the link, as they are giving several away throughout the holiday season. Today's game is Towerfall, which my kids tell me is excellent. A platformer from the old Ooya system ported to PC.